1. Field of the Invention
The present invention relates to a thin film magnetic bead and a method of manufacturing the same, and more particularly relates to a combination type thin film magnetic head having an inductive type writing thin film magnetic head element including a thin film coil and a magnetoresistive type reading thin film magnetic head element stacked one on the other, and a method of manufacturing the same. More particularly, the present invention relates to a combination type thin film magnetic head and a method of manufacturing the same, in which a GMR element is used as a magnetoresistive type thin film magnetic head element and an inductive type thin film magnetic head element has a superior NTSL property by extremely shortening a magnetic path length by reducing a coil winding pitch of a thin film coil and has a narrow record track for attaining a high surface recording density on a magnetic record medium by providing a miniaturized track pole made of a magnetic material having a high saturation magnetic flux density.
2. Description of the Related Art
Recently a surface recording density of a hard disc device has been improved, and it has been required to develop a thin film magnetic head having an improved performance accordingly. A recent magnetoresistive type thin film magnetic head using a GMR (Giant Magneto-Resistive) element has a surface recording density up to 100 gigabits/inch2. A combination type thin film magnetic head is constructed by stacking an inductive type thin film magnetic head intended for writing information on a magnetic record medium and a magnetoresistive type thin film magnetic head intended for reading information out of the magnetic record medium on a substrate. As a reading magneto-resistive element, a GMR element having a magnetoresistive change larger than a normal anisotropic MR element by 5-15 times has been used. In order to improve a performance of the GMR element, there have been various proposals.
In a normal anisotropic MR element, a single film of a magnetic material showing the magnetoresistive effect is utilized. Many GMR elements have a multi-layer structure having a stack of a plurality of films. A spin-valve GMR film has a relatively simple structure, generates a large resistance change under a weak magnetic field, and is suitable for a large scale manufacture. A performance of the reading head element is determined by not only the above mentioned selection of materials, but also by pattern widths such as an MR height and a track width. The track width is determined by a photolithography process and the MR height is determined by an amount of polishing for forming an air bearing surface (ABS).
At the same time, the performance of the recording magnetic head is also required to be improved in accordance with the improvement of the performance of the reproducing magnetic head. In order to increase a surface recording density, it is necessary to realize a high track density on a magnetic record medium. To this end, a pole portion of the recording thin film magnetic head element has to be narrowed in a sub-micron order, particularly not larger than 0.2 xcexcm by utilizing the semiconductor manufacturing process. However, upon decreasing a track width by utilizing the semiconductor manufacturing process, there is a problem that a sufficiently large magnetic flux could not be obtained due to a miniaturized structure of the pole portion. In this manner, by replacing the MR film by the GMR film in the reproducing head element and by selecting a material having a high magnetoresistive sensitivity, it is possible simply to attain a desired high surface recording density.
In order to realize a sufficiently high surface recording density of about 100 gigabits/inch2, it is necessary to use a record medium, i.e. a magnetic disk material having a high magnetic coercive force. If a magnetic material having a high coercive force is not used, once recorded data might be erased due to the thermal fluctuation. When a material magnetic having a high coercive force is used, recoding requires a large magnetic flux, and therefore a inductive type thin film magnetic head element must generate a large magnetic flux. Generally, in order to generate a large magnetic flux in the inductive type thin film magnetic head element, a track pole is made of a magnetic material having a high saturation magnetic flux density (Hi-Bs material having a saturation magnetic flux density not less than 1.8 T (tesla). NiFe (80:20) of 1.0 T and NiFe (45:55) have been used as a magnetic material having a high saturation magnetic flux density. Recently, CoNiFe of 1.8xcx9c2.0 T has been used. In order to use a miniaturized track pole stably, a magnetic material having saturation magnetic flux density of about 1.8 T is generally used. However, when a width of the track pole is reduced to sub-micron order, such magnetic materials could not generate a sufficiently large magnetic flux for recording stably. In this manner, it is required to use a magnetic material having a higher saturation magnetic flux density. Heretofore, when a track pole is made of a magnetic material having a high saturation magnetic flux density, a plating method has been generally used. However, in order to manufacture a track pole having a narrow width, it is preferable to use a sputtering method. From this view point, it will be advantageous to form a track pole by sputtered films of FeN having a saturation magnetic flux density of 2.0 T FeCo of 2.4 T.
FIGS. 1-9 are cross sectional views showing successive steps of a method of manufacturing a conventional combination type thin film magnetic head. In these drawings, A represents a cross sectional view cut along a plane perpendicular to the air bearing surface and B denotes a cross sectional view of a pole portion cut along a plane parallel to the air bearing surface. The combination type thin film magnetic head includes an inductive type recording magnetic head element provided on a magnetoresistive type reading magnetic head element.
As shown in FIGS. 1A and 1B, an alumina (Al2O3) insulating film 2 having a thickness of about 2-3 xcexcm is deposited on a substance 1 made of AlTiC. Next, a bottom shield film 3 made of a magnetic material for magnetically shielding a GMR reading head element from an external magnetic field on the substrate. On the bottom shield film 3, a shield gap film 4 made of alumina is formed with a thickness of 30-35 nm by sputtering. Then, a GMR film 5 having a given layer-structure is formed, and lead electrodes 6 for the GMR film are formed by a lift-off process. Next, a top shield gap film 7 made of alumina is formed with a thickness of 30-35 nm by sputtering, and a magnetic material film 8 serving as a top shield film is formed with a thickness of about 3 xcexcm.
Next, an isolation film 9 made of alumina is formed with a thickness of about 0.3 xcexcm for isolating the reading GMR head element from a writing induction type thin film magnetic head element to suppress noise in a reproduced output from the GMR head element. After that, a bottom pole 10 of the recording head element made of permalloy is formed with a thickness of 1.5-2.0 xcexcm. The bottom pole 10 is formed by a plating film of CoNiFe. It should be noted that in the drawings a ratio of thickness of various portions does not exactly correspond to an actual ratio. For instance, the isolation film 9 is shown to have a smaller thickness.
Next, as depicted in FIGS. 2A and 2B, on the bottom pole 10, is formed a write gap film 11 made of a non-magnetic material to have a thickness of about 100 nm, and a top track pole 12 made of a permalloy which is a magnetic material having a high saturation magnetic flux density is formed in accordance with a given pattern. At the same time, a bridge portion 13 for magnetically coupling the bottom pole 10 with a top pole to be formed later at a back-gap is formed. The top track pole 12 and bridge portion 13 are formed by plating with a thickness of about 3-4 xcexcm.
Then, in order to avoid a widening of an effective track width, i.e. in order to prevent a magnetic flux from extending at the bottom pole 10 during a writing operation, the write gap film 11 and the underlying bottom pole 10 around the top track pole 12 are etched by ion milling to form a so-called trim structure. After that, forming an alumina insulating film 14 having a thickness of about 3 xcexcm over a whole surface, a surface is flattened by the chemical mechanical polishing (CMP) as shown in FIGS. 3A and 3B.
Next, as illustrated in FIGS. 4A and 4B, in order to form a thin film coil by the electrolytic plating of Cu, a thin seed layer 15 having a thickness of about 100 nm is formed by sputtering. After forming a resist film having a given opening pattern on the seed layer, a first layer thin film coil 16 is formed with a thickness of 1.5 xcexcm in accordance with a given pattern by a plating process using a copper sulfate liquid. Then, after removing the resist film, the exposed seed layer 15 is removed by an ion milling process using an argon ion beam as depicted in FIGS. 5A and 5B. In this manner, the seed layer 15 is removed to separate coil windings to form a coiled conductor. During the ion milling, in order to prevent portions of the seed layer 15 projecting from side edges of the coil windings of the thin film coil 16 from being remained, the ion milling is performed at an angle of 5-10xc2x0. When the ion milling is carried out at an angle near a perpendicular angle, debris of the seed layer 15 splashed by impingement of the ion beam might be adhered again to the coil windings. Therefore, a distance between successive coil windings must be widened.
Then, as shown in FIGS. 6A and 6B, an insulating film 17 which supports the first layer thin film coil 16 in an electrically insolated manner is formed by photoresist. Next, as depicted in FIGS. 7A and 7B, a Cu seed layer 18 is formed and a second layer thin film coil 19 is formed in accordance with a given pattern with a thickness of 1.5 xcexcm. Then, after removing the seed layer 18 by ion milling, an insulating film 20 of photoresist for supporting the second layer thin film coil 19 in an electrically insulating manner is formed. Next, as illustrated in FIGS. 8A and 8B, a top pole 21 made of permalloy is formed with a thickness of about 3 xcexcm such that the top track pole 12 and bridge portion 13 are coupled with each other by the top pole 21, and a whole surface is covered with an overcoat film 22 made of alumina. It should be noted that during the formation of the second thin film coil 19, a connect portion 23 for connecting inner portions of the first and second thin film coils 16 and 19 is formed. Finally, an end surface into which the GMR film 5, write gap film 11, top track pole 12 and so on are exposed is polished to form an air bearing surface ABS to complete a slider. In a manufacturing process for forming an actual thin film magnetic head, after forming a number of the above mentioned structures on the wafer, the wafer is divided in a plurality of bars in each of which a number of thin film heads are aligned. Then, a side edge of the bar is polished to obtain the air bearing surface ABS.
FIG. 9 shows schematically a cross sectional view and a plan view illustrating the structure of the known combination type thin film magnetic head manufactured in the manner explained above. The bottom pole 10 has a large area, but the top track pole 12 and top pole 21 have a smaller area than the bottom pole. One of factors determining the performance of the writing head element is a throat height TH. The throat height TH is a distance from the air bearing surface ABS to an edge of the insulating film 14, and this distance is desired to be short. One of factors determining the performance of the reading head element is an MR height MRH. This MR height (MRH) is a distance from the air bearing surface ABS into which one edge of the GMR film 15 is exposed to the other edge of the GMR film. During the manufacturing process, a desired MR height MRH is obtained by controlling an amount of polishing the air bearing surface ABS.
There is another factor determining the performance of the thin film magnetic head together with the above mentioned throat height TH and MR height MRH. This factor is an apex angle xcex8, which is defined by an angle formed by a tangential line to a side wall of the insulating film 17 isolating the thin film coil 16 and an upper surface of the top pole 21. In order to miniaturize the thin film magnetic head, it is required to increase the apex angle xcex8 as large as possible.
Now problems in the known combination type thin film magnetic head mentioned above will be explained. After forming the insulating film 17, 20 such that the thin film coil 16, 19 is supported by the insulating film in an electrically insulating manner, the top pole 21 is formed. In this case, the top pole 21 has to be formed into a given pattern along the side wall of the insulating film 17, 20. To this end, a photoresist is formed with a thickness of 3-4 xcexcm at a step of the insulating film having a height of about 7-10 xcexcm. Now it is assumed that at the side wall of the insulating film 16, 19, the photoresist should have a thickness of at least 3 xcexcm, a thickness of the photoresist at the bottom of the step would become thick such as 8-10 xcexcm. Since a width of record track of the writing head is mainly determined by a width of the top track pole 12, it is not necessary to miniaturize the top pole 21 compared with the top track pole 12, but if the track width of submicron order such as 0.2 xcexcm is desired, the pole portion of the top pole 21 should be miniaturized in the order of submicrons.
Upon forming the top pole 21 into a desired pattern by plating, the photoresist has to be deposited on the top track pole 12 and insulating film 17, 20 having the step of more than 10 xcexcm such that the photoresist has a uniform thickness. Then, the photoresist is subjected to the exposure of light to form the top pole 21 having the pole portion of submicron order. That is to say, a pattern of submicron order should be formed with the photoresist having a thickness of 8-10 xcexcm. When the pole portion 21 is formed by plating, a seed layer made of permalloy serving as an electrode is previously formed. During the light exposure of the photolithography, light is reflected by the permalloy seed layer, and a desired pattern might be deformed. Therefore, it is quite difficult to form the pattern of submicron order precisely.
In order to improve the surface recording density, it is required to miniaturize the pole portion as explained above. Then, the miniaturized pole portion must be made of a magnetic material having a high saturation magnetic flux density. In general, FeN and FeCo have been known as magnetic materials having a high saturation magnetic flux density. However, these magnetic materials could not be easily formed by sputtering into a film having a given pattern. It has been known to shape the sputtered film into a given patter by the ion milling. However, etching rate is too slow and a track width of submicron order could not be controlled precisely.
NiFe, CoNiFe, FeCo have been known to have a high saturation magnetic flux density, and these magnetic materials could be formed into a given pattern by plating. For instance, Fe rich NiFe (more than 50%) has a saturation magnetic flux density of 1.5-1.6 tesla (T), and a composition could be controlled stably. However, in order to realize a surface recording density of 80-100 gigabits/inch2, a track width has to be not larger than 0.2 xcexcm. Then, there would be required to use a magnetic material having a higher saturation magnetic flux density. There has been proposed to form a magnetic film by plating using CoNiFe. However, this magnetic material could provide the magnetic faculty of about 1.8-2.0 T. In order to realize the surface recording density of about 80-100 gigabits/inch2, it is desired to use a magnetic material having a high saturation magnetic flux density such as 2T.
A high frequency performance of the induction type thin film magnetic head is also determined by a magnetic path length which is defined as a length from the throat height zero position to the back-gap. A high frequency performance of the thin film magnetic head is improved by shortening the above mentioned magnetic path length. It would be possible to shorten the magnetic path length by reducing a pitch of successive coil windings of the thin film coil, but this solution has a limitation. Then, there has been proposed to construct the thin film coil to have two coil layers as explained above. Upon forming the two-layer thin film coil, after forming a first thin film coil layer, an insulating film of photoresist is formed with a thickness of about 2 xcexcm. This insulating layer has a round outer surface, and thus upon forming a second thin film coil layer, a seed layer for electrolytic plating has to be formed on an inclined portion. Therefore, when the seed layer is etched by the ion milling, a portion of the seed layer hidden by the inclined portion could not be removed sufficiently and coil windings might be short-circuited. Therefore, the second thin film coil has to be formed on a flat surface of the insulating layer.
For instance, it is now assumed that a thickness of the first thin film coil layer is 2-3 xcexcm, a thickness of the insulating film formed on the first thin film coil layer is 2 xcexcm, and an apex angle of the inclined portion of the insulating film is 45-55xc2x0, an outer surface of the second thin film coil layer must be separated from the throat height zero reference position by a distance of 6-8 xcexcm which is twice of a distance from the throat height zero reference position to the outer surface of the first thin film coil layer. Then, a magnetic path length would be longer accordingly. When the thin film coil has space/line of 1.5 xcexcm/0.5 xcexcm and a total number of coil windings is eleven, six coil windings are provided in the first thin film coil layer and five coil windings are formed in the second thin film coil layer. Then, a length of the whole thin film coil becomes 11.5 xcexcm. In this manner, in the known thin film magnetic head, a magnetic path length could not be shortened, and a high frequency property could not be improved.
In the known combination type thin film magnetic head explained above, there is a problem of miniaturizing the writing inductive type thin film magnetic head element. That is to say, by reducing the magnetic path length LM, i.e. a length portions of the bottom pole 10 and top pole 21 surrounding the thin film coil 16, 19 as shown in FIG. 9, a flux rise time, non-linear transition shift NLTS and over write property of the inductive type thin film magnetic head element can be improved. In order to shorten the magnetic path length LM, a coil width LC of a portion of the thin film coil 16, 19 surrounded by the bottom pole 10 and the top pole 21 has to be shortened. In the known thin film magnetic head, the coil width LC could not be shortened due to the following reason.
In order to shorten the coil width Lc in the known inductive type thin film magnetic head element, a width of coil windings of the thin film coil must be shortened, and at the same time, a distance between successive coil windings must be shortened. However, in order to reduce an electric resistance of the thin film coil, a width of coil winding should be shortened only with a limitation. When the thin film coil is made of copper having a high conductivity, a width of coil winding could not be reduced less than 1.5 xcexcm, because a height of the thin film coil is limited to 2-3 xcexcm. If a width of coil winding is shortened not larger than 1.5 xcexcm, a property of the GMR film 15 might be deteriorated due to heat generated by the thin film coil. Furthermore, the bottom pole 10 and top pole 21 are also heated to expand and a serious problem of pole protrusion might occur and the thin film magnetic head might be brought into contact with the record medium. Therefore, in order to reduce the coil width LC without shortening a width of coil winding, a distance between successive coil windings must be shortened.
In the known thin film magnetic head, a distance between coil windings of the thin film coil 16, 19 could not be shortened. Now a reason of this will be explained. As explained above, the coil windings of the thin film coil are formed by the electrolytic plating method using the copper sulfate liquid. In order to deposit a copper film uniformly within the opening formed in the resist film formed on the seed layer, the seed layer is first formed with a thickness of 100 nm, and then the copper film deposited by the electrolytic plating on the seed layer through the opening formed in the resist film to form the coil windings. After that, the seed layer is selectively removed to separate the coil windings. The seed layer is removed by the ion beam milling using, for instance an argon gas, while the coil windings are used as a mask.
In order to remove the seed layer between successive coil windings, it is preferable to perform the ion beam milling from a direction perpendicular to the wafer surface. However, this result in a re-deposition of debris of the seed material and successive coil windings might not be separated well, and thus a distance between successive coil windings could not be shortened. Such a problem could be solved by effecting the ion beam milling at an angle of 5-10xc2x0, a sufficient ion irradiation could not be attained at a shadow portion of the photoresist film and the seed layer might be remained partially. Therefore, a distance between successive coil windings could not be shortened in order to prevent an insufficient insulation between coil windings. In the known thin film magnetic head, a distance between successive coil windings is long such as 0.3-0.5 xcexcm. If a distance between successive coil windings is shortened less than the above value, the above mentioned problem might occur.
When the thin film coil 16, 19 is formed by the electrolytic plating method as explained above, in order to keep a thickness of the thin film coil uniformly, a plating liquid such as a copper sulfate must be stirred during the plating. If a width of a wall defining the opening in the photoresist film is shorted in order to shorten a distance between successive coil windings, the thin wall might be broken due to the stirring of the plating liquid. Then, the thin film coil could not be formed accurately. Also from this point of view, a distance between successive coil windings of the thin film coil could not be shortened.
The NLTS property of the inductive type thin film magnetic head could be improved by increasing the number of coil windings of the thin film coil. In order to increase the number of coil windings without increasing the magnetic path length, the number of thin film coil layers has to be increased to four or five layers. However, then an apex angle might be increased and a narrow track width could not be attained. In order to keep an apex angle within a given range, it is preferable to limit the number of thin film coil layers to not larger than three, preferably two. Then, the number of coil windings could not be increased and the NLTS property could not be improved.
Furthermore, when two thin film coil layers are provided as explained above, the second layer thin film coil 19 could not be formed perpendicularly, because the insulating film 17 is not flat, but is inclined at a peripheral portion of the second layer thin film coil. For instance, when a thin film coil having a space not larger than 0.3 xcexcm with a thickness not less than 1.5 xcexcm, argon ions could not effectively go onto the seed layer 18 between successive coil windings at a portion in which the thin film coil is not formed perpendicularly. Moreover, since an angle of the ion milling differs between a central portion and a peripheral portion of the wafer, the seed layer 18 could not be removed sufficiently and might be remained partially. When a space between successive coil windings is short, even if argon particles enter into this narrow space, Cu particles carried out together with argon particles might be deposited on side wall of the coil windings. Such etching debris might short-circuit the coil windings.
In Japanese Patent Application Laid-open Publication Kokai Sho 55-41012, there is disclosed a thin film coil, in which first and second thin film halves are arranged alternately with interposing therebetween an insulating film. In FIG. 7 of the Publication, there is shown a thin film coil, in which first and second thin film coils of a first layer thin film coil are formed as coils of anti-clockwise direction, and first and second thin film coil halves of a second layer thin film coil are formed as coil of a clockwise direction, and inner contact pads are connected to each other and outer contact pads are connected to each other such that an electric current flows in a same direction. However, in this known thin film coil, after forming the first thin film coil half, an insulating film and a conductive film are formed on a whole surface by sputtering or vacuum deposition, and a mask is formed selectively on the conductive film. After that, a portion of the conductive film formed above the first thin film coil half is selectively etched such that a portion of the conductive film deposited in a space between successive coil windings of the first thin film coil half is remained to form the second thin film coil half. Therefore, the first and second thin film coil halves are not formed in a self-aligned manner and a distance between successive coil windings could not be shortened in the order of submicrons.
One of the inventors of the present application has proposed in U.S. Pat. Nos. 6,191,916 and 6,204,997 a method of manufacturing a thin film coil, in which after forming a first thin film coil half by the electrolytic plating process using a seed layer, a thin insulating film and a seed layer are formed on a whole surface, a photoresist film having openings at portions corresponding to spaces of successive coil windings of the first thin film coil half is formed, and a second thin film coil half is formed by the electrolytic plating process using the photoresist film as a mask. In this method of manufacturing the thin film coil, the first and second thin film coil halves can be formed accurately by the electrolytic plating.
However, since use is made of the photoresist film having a given patter of openings for forming the second thin film coil half, the first and second thin film coil halves could not be formed in a self-aligned manner. Therefore, it is difficult to shorten a space between successive coil windings in the order of quartermicrons.
The present invention has for its object to provide a thin film magnetic head, in which a coil width LC of a thin film coil of an inductive type thin film magnetic head is shortened by decreasing a space between successive coil windings and a magnetic path length LM is shortened to improve a performance of the head.
It is further object of the invention to provide a method of manufacturing easily and precisely a thin film magnetic head, in which a coil width LC of a thin film coil of an inductive type thin film magnetic head is shortened by decreasing a space between successive coil windings and a magnetic path length LM is shortened to improve a performance of the head.
It is another object of the invention to provide a combination type thin film magnetic head, in which a high frequency characteristic is improved by shortening a magnetic path length and a surface recording density can is improved by providing a fine pole chip of the order to quartermicrons, while undesired side write can be avoided.
It is still another object of the invention to provide a method of manufacturing a combination type thin film magnetic head, in which a high frequency characteristic is improved by shortening a magnetic path length and a surface recording density can is improved by providing a fine pole chip of the order to quartermicrons, while undesired side write can be avoided.
According to the invention, a thin film magnetic head comprises:
a first magnetic member made of a magnetic material and including a pole portion which is to be opposed to a magnetic record medium;
a second magnetic member made of a magnetic material and including a pole portion which constitutes an air bearing surface together with an end surface of the pole portion of the first magnetic member, said second magnetic member being magnetically coupled with said first magnetic member at a back gap remote from the air bearing surface;
a write gap film made of a non-magnetic material and being sandwiched between said pole portions of the first and second magnetic members at least at the air bearing surface;
a thin film coil having a portion arranged between said first and second magnetic members in an electrically isolated manner; and
a substrate for supporting said first and second magnetic members, write gap film and thin film coil;
wherein said thin film coil comprises:
a first thin film coil half having coil windings mutually separated by a given distance;
a second thin film coil half having coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner;
an insulating film formed to embed spaces between successive coil windings of the first and second thin film coil halves; and
a jumper wiring connecting electrically an innermost coil winding of one of the first and second thin film coil halves to an outermost coil winding of the other of the first and second thin film coil halves.
According to the invention, a combination type thin film magnetic coil including a substrate, an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element, said inductive and magnetoresistive type thin film magnetic head elements being stacked on the substrate to define an air bearing surface;
wherein said inductive type thin film magnetic head element comprises:
a first pole made of a magnetic material and extending inwardly from the air bearing surface;
a write gap film made of a non-magnetic material and formed on one surface of the first pole to extend inwardly from the air bearing surface over a distance at least equal to a length of a track pole;
a bottom track pole made of a magnetic material and formed on a surface of the write gap film opposite to a surface which is brought into contact with the first pole to extend inwardly from the air bearing surface over a distance at most equal to a length of the track pole;
a first non-magnetic material film extending inwardly over a given distance such that the first non-magnetic material film has a flat surface which is coplanar with a second surface of the bottom track pole opposite to a first surface which is brought into contact with the write gap film and an outer end surface of the non-magnetic material film which is brought into contact with an inner end surface of the bottom track pole remote from the air bearing surface defines a throat height zero reference position;
a top track pole made of a magnetic material and formed on the coplanar flat surface of the bottom track pole and first non-magnetic material film to form a track chip portion extending inwardly from the air bearing surface at least to the outer end surface of the first non-magnetic material film and an end surface of the track chip portion is exposed to the air bearing surface and a contact portion which is continued from the track chip portion and has a width larger than a width of the track chip portion;
a second non-magnetic material film made of a non-magnetic material and formed to surround an aligned side surface of the bottom track pole, first non-magnetic material film and top track pole and have a flat surface which forms a coplanar flat surface together with a second surface of the top track pole opposite to a first surface which is brought into contact with a flat coplanar surface of the top track pole, bottom track pole and first non-magnetic material film;
a thin film coil formed in an electrically isolated manner in an inner region with respect to an end surface of the second non-magnetic material film which is brought into contact with an end surface of the contact portion of the top track pole; and
a second pole made of a magnetic material and formed such that one end of the second pole is magnetically coupled with the contact portion of the top track pole and the other end of the second pole is magnetically coupled with the first pole at the back gap remote from the air bearing surface, said first and second poles surrounding a part of the thin film coil;
wherein said thin film coil comprises:
a first thin film coil half having coil windings mutually separated by a given distance;
a second thin film coil half having coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner;
an insulating film formed to embed spaces between successive coil windings of the first and second thin film coil halves; and
a jumper wiring connecting electrically an innermost coil winding of one of the first and second thin film coil halves to an outermost coil winding of the other of the first and second thin film coil halves.
According to the invention, a combination type thin film magnetic head including a substrate, an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element, said inductive and magnetoresistive type thin film magnetic head elements being stacked on the substrate to define an air bearing surface;
wherein said inductive type thin film magnetic head element comprises:
a bottom pole made of a magnetic material and formed on the substrate to extend inwardly from the air bearing surface;
a bottom track pole made of a magnetic material and formed on one surface of the bottom pole to extend inwardly from the air bearing surface over a distance equal to a length of a track portion;
a bridge portion made of a magnetic material and formed on one surface of the bottom pole to define a back gap remote from the air bearing surface;
a thin film coil formed on the one surface of the bottom pole, one surface of the thin film coil opposite to the bottom pole forming a flat coplanar surface together with the bottom track pole;
a write gap film made of a non-magnetic material and formed the flat coplanar surface of the bottom track pole and thin film to form a flat surface; and
a bottom pole made of a magnetic material and formed on the flat surface of the thin film coil opposite to the bottom track pole such that the bottom pole includes a top track pole aligned with the bottom track pole and is brought into contact with said bridge portion;
wherein said thin film coil comprises:
a first thin film coil half having coil windings mutually separated by a given distance;
a second thin film coil half having coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner;
an insulating film formed to embed spaces between successive coil windings of the first and second thin film coil halves;
a first jumper wiring connecting electrically an innermost coil winding of one of the first and second thin film coil halves to an outermost coil winding of the other of the first and second thin film coil halves; and
a second jumper wiring having one end connected to an innermost coil winding of the other of the first and second thin film coil halves.
In the thin film magnetic head and combination type thin film magnetic head according to the invention, it preferable that the coil windings of the first thin film coil half are formed by electrolytic plating and the coil windings of the second thin film coil half are formed by CVD. More particularly, it preferable that the coil windings of the first thin film coil half are formed by electrolytic plating of copper and the coil windings of the second thin film coil half are formed by Cu-CVD. However, according to the invention, the coil windings of the first and second thin film coil halves may be formed by electrolytic plating of copper. Furthermore, the insulating film provided between successive coil windings of the first and second thin film coil halves has a preferably a thickness of 0.03-0.15 xcexcm. This insulating film may be made of an inorganic material such as alumina, silicon oxide and silicon nitride, and more particularly the insulating film may be preferably made of alumina-CVD.
In the thin film magnetic head and combination type thin film magnetic head according to the invention, since the thin film coil is formed by the first and second thin film coil halves and spaces between successive coil windings of the first thin film coil half are set to a value slightly larger than a width of the coil windings, successive coil windings of the second thin film coil half can be formed in these spaces in a self-aligned manner. Therefore, distances between successive coil windings of the first and second thin film coil halves can be extremely shortened and a magnetic path length can be shortened. Then, characteristics such as the flux rise time property, NLTS property and over write property can be improved.
In the thin film magnetic head and combination type thin film magnetic head according to the invention, a space between successive coil windings of the first and second thin film coil halves may be preferably not larger than 0.2 xcexcm, and more particularly may be preferably set to a value within a range of 0.03-0.15 xcexcm. If a space between successive coil windings is smaller than 0.03 xcexcm, the coil windings could not be isolated well. If a space between successive coil windings is larger than 0.2 xcexcm, a magnetic path length of the thin film magnetic head could not be shortened effectively. As explained above, according to the present invention, by reducing a space between successive coil windings to not larger than 0.2 xcexcm, particularly to a value within a range of 0.03-0.15 xcexcm, a magnetic path length can be shortened less than a half of the conventional thin film magnetic head illustrated in FIG. 9 without decreasing a width of coil windings. According to the invention, a magnetic path length can be shorter than that of the inductive type thin film magnetic heads disclosed in the above mentioned U.S. Pat. Nos. 6,191,916 and 6,204,997. In this manner, the performance of the thin film magnetic head can be improved to a large extent.
In the combination type thin film magnetic head according to the invention, it is preferable that said top track pole and bottom track pole are formed by RIE (Reactive Ion Etching) in a self-aligned manner and the surface of the second non-magnetic material film opposite to the surface which constitutes the flat coplanar surface together with the surface of the top track pole is extended toward the first pole beyond the write gap film to form a trim structure. Furthermore, the thin film coil is preferably formed on the flat coplanar surface of the top track pole and second non-magnetic material film. The top track pole may be preferably made of FeN, FeCo, CoNiFe, FeAlN or FeZrN, and the bottom track pole may be preferably made of FeN, FeCo, CoNiFe, FeAlN, FeZrN or NiFe. In this case, CoNiFe, FeCo and NiFe films may be formed as a plating film, and FeN, FeCo, FeAlN and FeZrN films may be formed as a sputtering film.
According to the invention, a method of manufacturing a thin film magnetic head comprising:
a first magnetic member made of a magnetic material and including a pole portion which is to be opposed to a magnetic record medium;
a second magnetic member made of a magnetic material and including a pole portion which constitutes an air bearing surface together with an end surface of the first magnetic member, said second magnetic member being magnetically coupled with said first magnetic member at a back gap remote from the air bearing surface;
a write gap film made of a non-magnetic material and being sandwiched between said pole portions of the first and second magnetic members at least at the air bearing surface;
a thin film coil having a portion arranged between said first and second magnetic members in an electrically isolated manner; and
a substrate for supporting said first and second magnetic members, write gap film and thin film coil;
wherein said step of forming the thin film coil comprises the steps of:
forming a plurality of coil windings of a first thin film coil half mutually separated by a given distance;
forming a first insulating film over a whole surface of the first thin film coil half;
forming a conductive film on the first insulating film such that spaces between successive coil windings of the first thin film coil half;
removing a portion of the conductive film covering top surfaces of the coil windings of the first thin film coil half and the underlying first insulating film to form a second thin film coil half having a plurality of coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner and are electrically isolated from the coil windings of the first thin film coil half by the first insulating film;
forming a second insulating film to cover the first and second thin film coil halves; and
forming a jumper wiring connecting electrically an innermost coil winding of one of the first and second thin film coil halves to an outermost coil winding of the other of the first and second thin film coil halves.
According to the invention, a method of manufacturing a combination type thin film magnetic head including a substrate, an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element, said inductive and magnetoresistive type thin film magnetic head elements being stacked on the substrate to define an air bearing surface;
wherein a process of forming said inductive type thin film magnetic head element comprises the steps of:
forming a first pole made of a magnetic material;
forming a write gap film made of a non-magnetic material on a surface of the first pole;
forming a first magnetic material film on the write gap film;
performing a first etching process for removing the first magnetic material film except for a width which is at least equal to a distance from a position defining the air bearing surface to a throat height zero reference position;
forming a first non-magnetic material film in a space formed by the first etching process such that the first non-magnetic material film is brought into contact with the first magnetic material film at the throat height zero reference position;
polishing the first non-magnetic material film to form a flat coplanar surface together with a surface of the first magnetic material film opposite to a surface which is brought into contact with the write gap film;
forming a top track pole made of a magnetic material on the coplanar flat surface of the first magnetic material film and first non-magnetic material film to form a track chip portion extending inwardly from the air bearing surface at least to an end surface of the first non-magnetic material film and a contact portion which is continued from the track chip portion and has a width larger than a width of the track chip pole;
performing a second etching process of reactive ion etching using at least said top track pole as an etching mask to remove selectively the first non-magnetic material film and first magnetic film to form a bottom track pole;
forming a second non-magnetic material film in a space formed by the second etching process;
polishing the second non-magnetic material film to form a flat coplanar surface together with the top track pole;
forming a thin film coil in an electrically isolated manner in an inner region with respect to a boundary surface at which the first and second non-magnetic material films are adjoined; and
forming a second pole made of a magnetic material such that one end of the second pole is magnetically coupled with the contact portion of the top track pole and the other end of the second pole is magnetically coupled with the first pole at a back gap remote from the air bearing surface, said first and second poles surrounding a part of the thin film coil;
wherein said step of forming the thin film coil comprises the steps of:
forming a plurality of coil windings of a first thin film coil half mutually separated by a given distance;
forming a first insulating film over a whole surface of the first insulating film;
forming a conductive film on the first insulating film such that spaces between successive coil windings of the first thin film coil half;
removing portions of the conductive film covering top surfaces of the coil windings of the first thin film coil half and the underlying first insulating film to form a second thin film coil half having a plurality of coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner and are electrically isolated from the coil windings of the first thin film coil half by the first insulating film;
forming a second insulating film to cover the first and second thin film coil halves; and
forming a jumper wiring connecting electrically an innermost coil winding of one of the first and second thin film coil halves to an outermost coil winding of the other of the first and second thin film coil halves.
According to the invention, a method of manufacturing a combination type thin film magnetic head including a substrate, an inductive type thin film magnetic head element and a magnetoresistive type thin film magnetic head element, said inductive and magnetoresistive type thin film magnetic head elements being stacked on the substrate to define an air bearing surface;
wherein a process of forming said inductive type thin film magnetic head element comprises the steps of:
forming a first magnetic material film made of a magnetic material and constituting a bottom pole;
forming, on the first magnetic material film, a second magnetic material film constituting a bottom track pole and a bridge portion of a back gap;
forming a thin film coil on the first magnetic material film to be supported in an electrically isolated manner;
polishing the second magnetic material film and thin film to obtain a flat coplanar surface;
forming, on the flat coplanar surface, a write gap film made of a non-magnetic material to have a flat surface;
forming, on the flat surface of the write gap film, a third magnetic film constituting a top track pole and top pole, said third magnetic material film being brought into contact with the bridge portion;
forming a mask on the third magnetic material film at a position at which the top track pole is to be formed;
performing an etching process for selectively removing the third magnetic material film to form the top track pole and further selectively removing a portion of the write gap film surrounding the top track pole and the underlying second magnetic material film to form the bottom track pole; and
forming an overcoat film made of an electrically insulating material on a whole surface;
wherein the step of forming the thin film coil comprises the steps of:
forming, on said first magnetic material film, a plurality of coil windings of the first thin film coil half isolated from the first magnetic material film such that the coil windings are separated from each other by a given distance;
forming a first insulating film all over the first thin film coil half;
forming a second insulating film on an area except for a thin film coil forming region at which a second thin film coil half is to be formed;
forming, on said first insulating film covering the first thin film coil half, a conductive film such that spaces formed between successive coil windings of the first thin film coil half are filled with said conductive film; and
removing a portion of the conductive film covering top surfaces of the coil windings of the first thin film coil half and an underlying portion of the first insulating film to form a second thin film coil half having coil windings which are formed between successive coil windings of the first thin film coil half in a self-aligned manner and are electrically isolated by the first insulating film; wherein prior to forming said third magnetic material film, contact portions provided at ends of innermost and outermost coil windings of the first and second thin film coil halves are exposed, during the formation of the third magnetic material film, a first jumper wiring for electrically connecting a contact portion at the end of the innermost coil winding of one of the first and second thin film coil halves to a contact portion of the outermost coil winding of the other of the first and second thin film coil halves and a second jumper wiring connected to a contact portion at the end of the innermost coil winding of the other of the first and second thin film coil halves are formed with a same magnetic material as that of the third magnetic material film.
In a preferable embodiment of the method of manufacturing a combination type thin film magnetic head according to the invention, after forming the first insulating film on a whole surface of the first thin film coil half and prior to forming the conductive film on the first insulating film such that spaces between successive coil windings are embedded, a third insulating film is formed to cover the thin film coil forming region, a fourth insulating film is formed selectively, and then the third insulating film is removed to form spaces between successive coil windings of the first thin film coil half. By forming the fourth insulating film while the thin film coil forming region is covered with the third insulating film, the fourth insulating film could not be inserted into the spaces formed between successive coil windings of the first thin film coil half. Moreover, when the third insulating film is made of an organic material such as photoresist, polyimide and spin-on-glass which can be easily removed by a wet chemical etching, the spaces can be easily formed between successive coil windings of the first thin film coil half.
Furthermore, after forming the conductive film constituting the coil windings of the second thin film coil half, the conductive film may be selectively removed by CMP using an alkaline slurry or a neutral slurry or by a dry etching such as ion beam milling and sputter etching. Alternatively, the second conductive film and second insulating film may be first etched roughly by CMP and then may be precisely etched by a dry etching.
Moreover, in the method of manufacturing a thin film magnetic head as well as the method of manufacturing a combination type thin film magnetic head, the coil windings of the first thin film coil half may be preferably formed by electrolytic plating of copper and the coil windings of the second thin film coil half may be preferably formed by CVD of copper. However, both the first and second thin film coil halves may be formed by electrolytic plating of copper.
Moreover, a coil winding which situates most closer to the air bearing surface is preferably formed by the outermost coil winding of the second thin film coil half and a coil winding which situates most closer to the bridge portion constituting the back gap may be formed by the innermost coil winding of the second thin film coil half. In this case, a width of the outermost and innermost coil windings of the second thin film coil half is preferably larger than that of the remaining coil windings. Then, even if a position of the first thin film coil half is deviated, a width of these outermost and innermost coil windings might not be small and a resistance value might not increase excessively.
In a preferable embodiment of the method of manufacturing a combination type thin film magnetic head according to the invention, during said etching process, after forming the bottom track pole, RIE is continued to remove the write gap film selectively, and further the bottom pole is partially etched over a part of its thickness to form a trim structure in a self-aligned manner. In this case, the step of forming the top track pole includes a step of forming the second magnetic material film on the flat surface of the first magnetic material film and first non-magnetic material film to have a flat surface, a step of forming, on the flat surface of the second magnetic material film, a mask having a pattern corresponding to the shape of the top track pole to be formed, and a step of selectively removing the second magnetic material film by RIE using the mask, and then this RIE is continued and the first magnetic material film is etched to form the bottom track pole in a self-aligned manner. The first magnetic material film may be advantageously made of FeN or FeCo, and the second magnetic material film may be formed by plating of FeN or FeCo. The RIE process for removing the first and second magnetic material films may be preferably performed at a high etching temperature above 50xc2x0 C., particularly 200-300xc2x0 C. under an atmosphere of Cl2 or a mixed gas of Cl2 and boron series gas such as BCl2 or a mixed gas of Cl2 and an inert gas such as Ar and N2.
In a preferable embodiment of the method of manufacturing a combination type thin film magnetic head according to the invention, said step of forming the top track pole includes the steps of:
forming the second magnetic material film on the flat surface of the first magnetic material film and first non-magnetic material film to have a flat surface; and
forming the top track pole by RIE using a mask formed on the flat surface of the second magnetic material film and having a pattern corresponding to the shape of the top track pole;
wherein RIE is performed to etch the first magnetic material film to form the bottom track pole in a self-aligned manner, while said top track pole is used as an etching mask. In this case, the latter RIE may be conducted under a same condition as the former RIE.
In the method of manufacturing a thin film magnetic head and the method of manufacturing a combination type thin film magnetic head according to the invention, it is preferable that said insulating film for isolating the first and second thin film coil halves may be preferably formed by alumina-CVD. The alumina-CVD may be preferably a reduced pressure Al2O3-CVD film formed by an atomic layer process, in which Al(CH3)3 or AlCl3 and H2O, N2, N2O or H2O2 are alternately projected intermittently under a reduced pressure of 1-2 Torr at a temperature of 100-300xc2x0 C., preferably 150-200xc2x0 C. In this manner, it is possible to obtain the insulating film having a superior step-coverage and containing no key hole and void, and thus an excellent electrically insulating property can be attained although the insulating film has a large thickness.